城市地下既有建筑物桩基探查与评价技术研究

Pile Foundation Exploration and Evaluation Technology for Urban Underground Existing Buildings

随着城市建设不断发展,既有建筑物在计划重建或续建时需对既有桩基础进行有效探查,以寻可否再利用、降低功能使用或进行既有桩基清除。依托实际工程案例,对既有桩基探查评估技术进行分析研究,通过对场地进行补充勘验直接获取桩周土层参数,开展钻芯法试验验证桩身混凝土强度;开展磁测井法试验判定基桩钢筋笼长度;基于补充勘验地层参数并结合原位静力触探法与经验参数法,估算静力触探孔附近的冲孔灌注桩的单桩极限承载力;通过自动化监测技术对大厦拆建过程中地基的沉降变化规律进行了研究,实现了自动化监测技术在既有地下室结构的成功应用。通过分析研究,初步形成成套既有建筑桩基整体评估技术,可为今后类似工程提供指导和借鉴。

With the continuous development of urban construction,it is often necessary to effectively explore the existing pile foundation during the planned reconstruction or continuation to find out whether it can be reused,reduce the function or remove the existing pile foundation.Based on actual engineering cases,this work analyzed the existing pile foundation exploration and evaluation technology,and directly obtained the soil layer parameters around the pile through supplementary inspection of the site,and conducted core drilling method tests to verify the concrete strength of the pile body.Magnetic well testing was conducted to determine the length of the foundation pile reinforcement cage.Based on supplementary investigation of geological parameters and combined with in-situ static penetration method and empirical parameter method,the ultimate bearing capacity of a single pile near the static penetration hole is estimated.Through the use of automated monitoring technology,the settlement changes of the foundation during the demolition and construction process of the building were analyzed,and the successful application of automated monitoring technology in existing basement structures was achieved.Finally,,a comprehensive evaluation technology for existing building pile foundations has been preliminarily formed,which can provide guidance and reference for similar projects in the future.